Archive for Shahriar Shahramian

Teardown & Repair of an Agilent N9020A MXA 10Hz – 8.4GHz Spectrum Analyzer (November 2019)

In this episode Shahriar troubleshoots a defective Agilent N9020A 8.4GHz spectrum analyzer. The instrument reports LO Unlock and refuses to perform any sweep at all. The complete block diagram of the instrument is presented with focus on the LO generation blocks.

The teardown of the instrument reveals the individual assemblies presented during the block diagram overview. After a few measurements, it is concluded that the LO Synthesizer module is faulty. The module is presented in detail and various components and signal paths are identified. Extensive measurements are carried out until the fault is traced to problems in the varactor bank of the main VCO. After the component replacement, the instrument is fully functional. The X-Ray of the synthesizer module is also presented during the repair.

Teardown & Repair of an Agilent 1169A 12GHz Smart Active Probe (And a Puzzle!)

In this episode Shahriar examines a failed Agilent 1169A 12GHz Smart Active Probe. The probe does not get recognized by the oscilloscope and therefore cannot be calibrated. The instrument uses an I2C interface to the probe to download the probe’s specifications and characteristics.

The probe teardown reveals a simple I2C EEPROM IC. After removing the IC it becomes clear that the chip is damaged and must be replaced. A duplicate probe is used to copy the EEPROM data onto a new IC which revives the probe. With the help of the community, the CRC checksum code is discovered and the probe is assigned a new serial number.

Siglent SVA1032X 3.2GHz Spectrum & Vector Network Analyzer Review, Teardown & Experiments

In this episode Shahriar reviews the newly released Siglent SVA1032X. The SVA series instrument spectrum & vector network analyzers are powerful and flexible tools for broadcast and RF device / system testing. With a wide frequency range covering 9 kHz to 3.2 GHz, the analyzer delivers reliable automatic measurements and plenty of features including a tracking generator and multiple modes of operation. This review is organized as follows:

00:09 – Introduction and instrument overview
02:25 – Complete teardown and detailed analysis of the instrument hardware
23:36 – Basic instrument GUI operation and overload detection limitations
28:38 – Tracking generator signal purity and performance
30:06 – Instrument internal phase noise performance
33:01 – VNA operation and amplifier impedance tuning experiment
39:28 – Amplifier characterization using built-in functions
44:20 – Digital demodulation experiments
49:30 – Distance to fault experiments using built-in functions
49:16 – Concluding remarks

Tektronix AFG31000 2GS/s Arbitrary Function Generator Review, Teardown & Experiments

In this episode Shahriar reviews the new Tektronix AFG31000 Arbitrary Function Generator. The AFG31000 series with InstaView™ technology is the first high-performance AFG with built-in waveform generation applications, patented real-time wave monitoring, and a modern user interface. The instrument is capable of 2GS/s waveform generation up to 250MHz and 14-bits of vertical resolution. This review is organized as follows:

00:08 – Introductions
01:01 – Front panel, rear panel and instrument design
03:44 – Detailed teardown, analysis, architecture and components
17:30 – GUI overview and basic functions
20:25 – Broadband FM modulation experiments
23:55 – InstaView experiments with a non-linear impedance
35:38 – Equation editor, waveform builder and advance sequencing
51:21 – Concluding remarks

Teardown, Repair & Analysis of a Rohde & Schwarz FSEK 20Hz – 40GHz Spectrum Analyzer

In this episode Shahriar takes a look at a non-functional R&S FSEK 40GHz spectrum analyzer. The instrument’s LCD screen back light no longer works and the front glass is broken. Furthermore, no testing can be done until these problems are resolved. The CCFL tube is replaced with an LED counterpart and a new front panel glass is also installed.

After power on it becomes clear that the instrument has other defects. The internal PLL is unlocked. It is observed that the OCXO module is cold and potentially not working. Examination of the LO board shows a bad inductor on the DC filter side. After this problem the instrument operates correctly but only for signals below 7GHz. After further testing it is discovered that the YIG tuned filter on the pre-selector path is not tuning at all. Eventually the fault is traced to some operational amplifiers on the YIG driver board. The repaired instrument is verified for correct operation.

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